Network connection problems

I have a LAN setup at home, all of a sudden no computers can connect to the internet that are connect via a wire, any devices connected via the wireless are fine. Its only wired devices/pcs that are affected. I can't even ping the wired pcs??

If no changes were made to the router/switch and the physical ports are up it could be DHCP stopped working or something like that. You may want to power cycle the router if you haven't already.

If you open a command prompt and use the ipconfig /all command are the PC's getting IP addresses from the DHCP server function of the router/switch?
If not can you configure a manually assigned address on a PC and get connectivity that way?

Generally speaking if the wired and wireless clients are running off the same router the address range should be the same. What are the wireless devices showing for their IP addresses?